LED lighting system

ABSTRACT

A lighting system includes at least one lighting apparatus having a light emitting element capable of emitting a controllably variable light output in a region. A position determination subsystem is capable of determining a position in three dimensions of at least one mobile entity within the region. A control subsystem is capable of variably controlling a light output of the at least one lighting apparatus according to the position of the mobile entity. The system may determine position by radio ranging with mobile electronic elements. The system may include multiple lighting elements and may determine light levels according to positions of multiple mobile entities. The system may include a database of information about lighting elements, mobile entities, and lighting plans that may be selected from mobile electronic elements.

CROSS-REFERENCE TO RELATED APPLICATIONS

None.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

None.

NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

None.

BACKGROUND

Lighting usually is an integral part of an office, factory, store,supermarket, hospital, home, other building, parking lot, walkway,roadway, park or other improved location. Light fixtures most commonlyare located in close proximity above or on the sides of locations thatpeople tend to occupy. A typical building incorporates a range offixtures to address occupants' needs. For example, a building may use 2foot, 4 foot, or 8 foot fluorescent light fixtures with differentwattages, light angles and mounting requirements. Open spaces may usefixtures of differing size and power.

Commercial buildings and other lighting typically involves the use oflighting fixtures that can only be turned on or off, such as by amechanical switch, a motion detector, a light sensor switch or a timer.Some offices and outdoor security lighting use motion detectors withlight sensors to trigger the switching of lights. If the timer is settoo long, it wastes energy. If timer is set too short, it annoys itsoccupants. (The term “occupant” is not intended to be limited tointerior building occupants but to occupants of any lighted space.)Furthermore, if an obstruction blocks a motion sensor, or if an occupantis beyond sensor range, the lighting scheme may not work at all.Occupants are often annoyed by the automatic switching off the lightswhen an occupant remains in a space beyond the timer period, such as bysitting still using a computer or reading a book.

SUMMARY

An objective of the invention is to provide improved lighting fixturesand systems. A further objective is to provide lighting systems withenhanced intelligence. Yet another objective is to provide lightingfixtures and systems that better adapt to occupant needs andenvironmental factors to provide enhanced productivity, security, assettracking, occupant health monitoring, and other goals. Other objectivesinclude:

(A) providing lighting that is more efficient than incandescent andfluorescent lights;

(B) providing lighting fixtures suitable for retrofit to existingbuildings or installation in newly-constructed buildings; and

(C) providing lighting fixtures suitable for stand-alone operation oroperation that coordinates multiple fixtures;

These and other objects may be achieved by providing lighting fixturesand systems designed with light emitting diodes (LEDs) that may be moreefficient than fluorescent lights. Preferred fixtures may have modulesthat are 22 inches in length and optional numbers of LEDs in strips withvariable output wattages and color temperatures. The modules can bechained together to achieve longer lengths. LED light strips preferablyhave several segments which may be individually driven or commonlydriven. In the event that LEDs in some but less than all segments shouldfail, the LEDs in the other segments would remain functional. Thisovercomes a draw back in incandescent and fluorescent light fixturesthat may go totally dark upon failure of an individual bulb. Fixturesmay provide different color lights for each individual LED segment. Theuse of Red, Blue and Green LEDs for each segment allows the fixture toprovide a selectable color chromaticity. An output level and/orchromaticity will be referred to here as a light plan. Fixtures mayinclude capability for performing some or all of the followingfunctions:

a) Self reporting of power usage and power consumption histories andpatterns.

b) Automatic control of light fixture usage due to:

-   -   i) environment (e.g., ambient light, time of day, etc.),    -   ii) motion detectors sensing the presence and/or activity of        people,    -   iii) behavior or pattern of occupants, and/or    -   iv) proximity of users and events;

and/or

c) Security and/or backup lighting for security and/or safety.

Lighting usage may be adjusted according to social behavior patterns.Social behavior may be captured by associating a wearable or otherwiseportable device carried by occupants, such as a badge embedded with RFIDdevices, a cell phone, or other another electronic device that has atraceable unique identifier. Lighting fixtures may be assigned with aunique identifier and may communicate with portable devices to form adynamic wireless network, such as a Zigbee network. A database may beprovided to maintain information about portable devices, fixtures, andother information.

The early sections of the description below discuss lighting fixturesand their mechanical parts and assembly. Among other things, theydescribe a modular feature and a reflector that can adjust its angle totailor light distribution to room requirements. The LEDs can cascade tovarious lengths according to room requirements while still powered bythe same power source and drivers.

Then, circuit designs of LED drivers for lighting fixtures are shownwith electrical details of how fixtures may be powered by one or moredrivers under cascading conditions. The intensity of LED chains may bevaried by a dimming capability of drivers and controllers. Alternativecircuit configurations of drivers, jumpers and temperature controls areshown which facilitate LED function and longevity. LEDs can have 50,000to 60,000 hours of lifetime compared to 8,000 to 10,000 hours forfluorescent lights.

Final sections discuss the use of microcontroller systems in thefixtures, portable devices worn by the users and network serverscontrolling, recording and coordinating lighting functions.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

Reference will be made to the following drawings, which illustratepreferred embodiments of the invention as contemplated by theinventor(s).

FIG. 1. Light fixture parts assembly.

FIG. 2. Type B ceiling support bracket.

FIG. 3. Type C corner support bracket.

FIG. 4. Type A flat surface support bracket.

FIG. 5. Fixture back cover.

FIG. 6. Detail features of a fixture back cover.

FIG. 7. Light diffuser unit.

FIG. 8. Light reflector unit.

FIG. 9. Rotate block A.

FIG. 10. Rotate block B.

FIG. 11. LED light/reflector rotation system.

FIG. 12. Type A end cover.

FIG. 13. Type A end cover details.

FIG. 14. Type B end cover.

FIG. 15. Type B end cover details.

FIG. 16. Cable rotate block side view

FIG. 17. Cable rotate block front view.

FIG. 18. Cable conduit.

FIG. 19. LEDs light strip.

FIG. 20. LEDs light strip circuit assembly.

FIG. 21. LEDs strip circuit diagram with PTC components.

FIG. 22. LEDs strip circuit diagram with shorting end jumpers.

FIG. 23. Cascading of two fixture modules with end jumpers.

FIG. 24. Triple LEDs chain driver circuit.

FIG. 25. Single LED driver configuration.

FIG. 26. Cascading of two LED fixtures with short end and driver frontjumpers.

FIG. 27. PTC regulatory circuit design.

FIG. 28. End circuit jumpers for a 3 LED circuits.

FIG. 29. The PTC regulation design in a three LED driver circuits.

FIG. 30. PTC regulation design in a one LED driver circuit.

FIG. 31. NTC regulatory circuit design.

FIG. 32. NTC regulation design in a three LED driver circuits

FIG. 33. NTC regulation design in one LED driver circuit.

FIG. 34. Type A connector.

FIG. 35. Type B connector.

FIG. 36. Bracket Latch.

FIG. 37. Illustration of an Intelligent Lighting network.

FIG. 38. Wireless Network Map.

FIG. 39. Brightness control feedback loop

FIG. 40. Light Sensor Microcontroller control via an I2C communication.

FIG. 41. A controller system with intelligence.

FIG. 42. Light Illumination Plan A—Ultra Savings.

FIG. 43. Light Illumination B—Moderate Savings.

FIG. 44. Light Illumination C—Nominal Savings.

FIG. 45. Light Illumination C—Nominal Savings with Walking.

FIG. 46. MCU controlling a wireless RF Chip CC2500.

FIG. 47. CC2500 Pin Configuration and Pin function

FIG. 48. MSP430 Communication Pins.

FIG. 49. CC2500 components values.

FIG. 50. Flowchart for a Mobile Tag.

FIG. 51. Distance measurements from RSSI.

FIG. 52. Example Front view of mobile tag (End Device)

FIG. 53 Access point Flow Chart.

FIG. 54. Master Network Server.

FIG. 55. Master Network Server flow chart Part 1.

FIG. 56. Master Network Server flow chart Part 2.

FIG. 57. Master Network Server flow chart Part 3.

FIG. 58. Additional AC voltage and current sense IC interface.

DETAILED DESCRIPTION OF THE INVENTION

A need exists for intelligence in responding to lighting needs of theusers or occupants of a building, walkway, or other indoor or outdoorplaces that people may occupy. Activities determine how bright alocation may need to be. People occupying spaces where the lightfixtures are installed often have unspoken social interactions andintentions. A light fixture output should respond to the needs andrequirements of the occupants, their activities, and the environment.Environmental factors also influence lighting needs, such as interior orexterior location, proximity to windows (if interior), other lightsources and time of day. Consider, for example, a person walking acrossa very large space, such as a conference room, long hallway, parkinglot, or sidewalk. The person would expect good lighting conditions inthe direction of travel. However, to light up an entire area equallywith constant brightness would be energy inefficient. Therefore anautomatic adaptation of the lighting conditions in the direction oftravel would conserve energy. A janitor, who cleans the officesespecially during the night would need the light levels to be high toperform a good job. A person working on a computer and looking at ascreen would like to have the room light level to be less then forreading a book. The room lights should not cause glare or compete withthe computer monitor brightness. Adjusting lights with the right levelwould not only save the lighting energy, it would save the computermonitor's energy too. It is useful to track positions occupants relativeto lights sources.

Light fixtures preferably will be installed in fixed locations in everyroom throughout a building or at regular intervals in exterior spaces.Their locations preferably will be non-obstructive and strategicallypositioned where the occupants would use the light for carrying outtheir activities. Most likely these fixtures would be installed abovepeople's heads and therefore provide a good planar arrangement definingthe ground or floor level. Staircase lightings would appear as betweenlevels.

FIG. 1 shows selected components of one embodiment of a preferred LEDlighting fixture, referred to here as a “type B” fixture to distinguishit from other fixture types discussed further below. Such a fixture mayinclude: a light diffuser 2, a back cover 4, a type B connector 6, atype B end cover 8, a rotate block A 10, one or more type A supportbrackets 12, one or more reflectors 14, a cable conduit 16, a cablerotate block 18, one or more LED light strips 20, a type A end cover 22,a type A connector 24, and a rotate block B 26.

FIG. 2 shows a type B support bracket for alternate mounting of thefixture and adaptation to a choice of mounting methods. This may replacethe type A bracket 12 shown in FIG. 1. This bracket supports the fixturefrom above through a hole 50 in chain bracket. Such a hole 50 allows thebracket to connect via either chain or other vertical architecturalstructure. It has a set of angle flaps 56 which connect to a back cover4 (FIG. 1, item 4) of a fixture with a hooked edge at the ends thatsecures the fixture. The bracket first may be secured to a buildingsupport, and then the fixture may be snapped in place.

When two fixtures are joined together end-to-end, a bracket may beplaced across the joining ends of the fixtures. A set of cut-out slots54 preferably grips two fixture end covers and locks them in place.

Type C Corner Support Bracket

FIG. 3 shows a type C support bracket, which may be used for cornerfixture mounting. This may replace the type A bracket 12 shown inFIG. 1. Two flaps 62 are similar to type B bracket flaps 56 except forholes 60. These holes 60 may be used for screw mounting to a cornerlighting location. Slots 64 may be used similarly to the two cut-outslots 54 in FIG. 2 to join adjacent fixtures.

An outer surface of the bracket flaps 62 can also serve as a surface fora double sided tape or Velcro piece to secure the bracket to anysurfaces. This would make mounting flexible for many surfaces.

Type A Flat Surface Support Bracket

FIG. 4 shows a type A support bracket, which may be used for mounting toa ceiling or other surface. This type of support bracket is also shownin FIG. 1. A hole 72 can be used to screw the fixture to any flatsurface. A bracket surface 70 alternately may serve as a surface for adouble-sided tape or Velcro piece to secure the bracket to manysurfaces. This would make mounting flexible for many surfaces.

Flaps 76 may be similar to flaps 56 of the type B bracket shown in FIG.2, except that that they may flare outwardly 74, to accommodate thesurface 70. The lengths of the flaps 74, 76 may be varied to provide adesired height to the fixture. This bracket allows the fixture to bemounted within another fixture, such as within an existing fluorescenttube fixture where the tube may be absent.

Fixture Back Cover

FIG. 5 shows a preferred back cover (FIG. 1, item 4) as an angled piece80 with two, generally-flat surfaces and a protruded lip on the longedges 84. There may be two holes 82 on each short edge to securetriangular end cover pieces (FIG. 1, items 8, 22) with screws. Detailsof lips 84 are shown in FIG. 6. These lips may be used to secure a lightdiffuser 2 to a back cover 4. A track allows a flat diffuser 2 to slidein from the ends.

Light Diffuser

FIG. 7 shows an exemplary light diffuser (FIG. 1, item 2) having a flatform. A diffuser may be made of transparent material 90 which haspatterns to diffuse any spot appearance of LED lights. It preferablywould be a light weight plastic, glass, or other material. The diffuserpreferably lets light through efficiently but in a diffused manner.Diffusers such as those used in fluorescent light fixtures may bepatterned plastic material, though they might not be the most efficient.A preferred, more efficient light diffuser would be a Fresnel diffuser.These diffusers may have transmission efficiencies greater thanninety-eight percent. The entire diffuser piece can be made of thisFresnel type. An example is a clear acrylic material with aDIFF_RDN_(—)20_R/20 FWHM random diffuser finish on one side from FresnelTechnologies, Inc. Wide diffusion angles of twenty degrees or more arepreferred if the spotty look is to be minimized. Alternately, a diffusercan have localized Fresnel pattern areas, such as circular patches 92where the Fresnel random diffuser is aligned in front of each LED spoton a light strip 20. Other areas beyond these patches can be eithertransparent or translucent. These diffusers may be fabricated from laserholography plastic cutting techniques on sheet plastic materials.

Light Reflector Unit

FIG. 8 shows an exemplary, curved light reflector (FIG. 1, item 14) witha body 100 and two guide rails 104. Such a reflector has holes 102 topermit access to LED light sources. Guide rails 104 have fingers tosecure an LED light strip 20. Sandwiched between the LED light strip andthe reflector may be a piece of thermally conductive elastomer withholes matching holes of the reflector. This elastomer piece may beelectrically insulated or insulative. The reflector front preferably hasa highly reflective surface 106 which may be an electroplated or plasticplated surface with a protective coating. A reflective adhesive foilwould be one of many an alternate solutions. The reflector may be madeof thermally conductive material. Preferably, it could be metallic orplastic material loaded with thermally conductive particles, such asbarium titanate or strontium titanate.

Rotate Block A

FIG. 9 shows a first, A-type, rotate block (FIG. 1, 10). It may becomprised of an LED light strip mounting body section 110, a round disksection 114, a rod rotation section 118, and a rotate coupling connector116. Two screw holes 112 in the body section 110 may be used formounting an LED light strip (FIG. 1, item 20). Screw holes 112 may beused to rigidly secure the rotate block to an aluminum plate 206illustrated in FIG. 20. This block enables an LED light strip to rotate,either manually by a screw driver at the end or by an electricallycontrolled by a coupling stage.

Rotate Block B

FIG. 10 shows a B-type, rotate block (FIG. 1 item 26). It may be similarto an A-type rotate block, except for the absence of a rotate couplingconnector 116.

FIG. 11 shows a detailed view of elements used in adjusting an angle ofa light fixture. An end cover 160 has a hole 166 for receiving a rod 138from rotate block B 164. A spring 162 may be placed over the rod 138 topress against a disc of rotate block B (FIG. 10, item 136). An LEDlight/reflector assembly 168 may attach to rotate block B by screwsthrough holes in rotate blocks A and B (FIG. 9, item 112 and/or FIG. 10,item 134). The spring tension at the disc 136 also pushes against a discof block A (FIG. 9, item 114). The disc 114 also presses against ageared/rough surface ring 172 in end cover 174. The disc 114 is inengaged mode and holds an angle for the reflector assembly. By fitting ascrew driver through hole 176 into a slot 178 and pushing against thespring compression, the disc disengages from the fixed ring 172. Turningthe screw driver then freely rotates the reflector assembly 168. A usermay see the light corresponding to the adjusted angle in real-time. Oncea desired angle is achieved, the user can withdraw the screw driver, andthe disc 114 will once again press against ring 172 and hold the fixtureengaged in the set angle. The spring maintains a pressure to hold thedisc engaged with the ring 172.

Type A End Cover

FIG. 12 shows an exemplary, Type A, end cover (FIG. 1, item 22). Thiscover may be a triangular-shaped end body piece 120 with three openings.This cover may be secured within the inside back cover of a lightfixture (FIG. 1, item 4) via screw holes 126 on two sides of the cover.The back cover (FIG. 1, item 4) preferably retains a smooth surface. Acircular opening 122 allows the rotate coupling connector (FIG. 9, item116) of Rotate Block A (FIG. 1, item 10) to fit through. A rectangularopening 128 may allow access for an electrical connector (e.g., FIG. 1,items 6, 24) to the next fixture module. A rectangle opening 124 may beincluded as a venting hole.

FIG. 13 shows an alternate view of Type A end cover 22. The rotate blockA 10 preferably fits through a circular hole 122 and stays within thefront surface of the cover 22 having a lip 130 around its edge.

Type B End Cover

FIG. 14 shows an alternate, type B, end cover (FIG. 1, item 8). Thiscover has a concealed circular ring 194, which may be a support for arod rotation section (FIG. 10, item 138) in rotate block B and holds inplace a curved reflector (FIG. 1, item 14) in a user-adjusted angle ofrotation. A circular opening 196 allows cable rotate block (FIG. 1, item18) to fit through from an outer surface. Similar to the Type A endcover, there may be screw holes 192 on two sides of the cover. A smallerrectangular opening 190 may be provided as a vent hole.

FIG. 15 shows an alternate view of Type B end cover (FIG. 1, item 8). Acircular ring 194 in FIG. 14 may be concealed from this outer view ofthe cover. If a hole through the circular ring 194 is opened, a rotationrod adapted to be turned with a screw driver may slide to acorresponding hole in the next module and engage with the rotation rodin the adjacent module to rotate the other module's reflector assembly.

Cable Rotate Block

FIG. 16 shows an exemplary cable rotate block (FIG. 1, item 18). Thisblock has a body 180 with a power cable entrance path 182 that entersthe fixture through a passage 184. A rotate shaft 186 and a splitcoupler 188 preferably fit through a hole in a triangular end cover(e.g., FIG. 12, item 122).

FIG. 17 shows an alternate view of the cable rotate block of FIG. 16. Acable enters from a cable conduit (FIG. 1, 16), goes into a cavity 182,makes a right turn into hole 184, and feeds into the fixture. A splitcoupler 188 prevents the rotate block from slipping out of an end-coverhole (e.g., FIG. 15; item 194). The block can rotate freely with respectto an end cover.

Cable Conduit

FIG. 18 shows a cable conduit (FIG. 1, item 16). It may be made of ahollow rod 140, and it can be made of any appropriate length. In thismanner, the cable may be shielded by the conduit. This conduit can bemade of plastic or metal.

LED Light Strip

FIG. 19 shows an exemplary LED light strip (FIG. 1, item 20). Circulardots 152 represent LEDs mounted preferably on a flexible circuit 154,which in turn may be mounted on aluminum bar 156. The screw holes 150 onboth ends of the bar allows rotate block A (FIG. 1, item 10) and rotateblock B (FIG. 1, item 26) be mounted.

FIG. 20 shows an exemplary assembly of an LED light strip with reflectorand heat sink. LEDs 200 may be soldered or otherwise attached onto acopper flex circuit 202. The flex circuit substrate may be about 25 to75 microns thick, which would allow heat to transfer easily in the Zdirection orthogonal to the flexible circuit surface. The substratematerial may be an insulator made preferably of one of the followingmaterials, though other materials may be used:

a) Kapton™ (Polyimide film)

b) PEN (Polyethylene Naphthalate film such as Teonex, Teijin, Dupont)

c) PET (Polyethylene Terephthalate film from Dupont)

The flex circuit conductive traces may be two ounce copper, about 2.8mils thick, for both low resistance and good thermal conductivity.Control signal traces may be low current circuits. Additive printedthick film technology (PTF), such as silver ink, can be used. Conductivetraces may be routed with design rule to retain most of the conductivecopper. An LED heat sink may be mounted on the copper pads with solderor heat sink compound to promote heat dissipation. The flexible circuit202 may be attached to the aluminum block or plate 206 via a hightemperature, double sided adhesive tape 204. An aluminum heat sink platemay be formed into a one-dimensional parabolic shape and electroplatedwith a highly reflective coating to be used as the LED light reflectorsimultaneously. An example of an adhesive tape is the 3M #467 MP tape.This tape has a thickness of approximately 50 microns and allows bothsurfaces come into good contact for good thermal transfer. A hightemperature, thermally conductive, electrically insulative, siliconegasket 208 with holes for LED components to pass through may be usedbetween the reflector 14 and the LED Flexible circuit 202.

FIG. 21 shows an exemplary circuit diagram for a six-LEDs strip formedin three chains A, B, C. Paths A, B, C, D, E and F may be consideredhigh current LED power circuits. D, E, and F may be used for LED currentreturn. Two LEDs 210, 212 may be on Chain A, two LEDs 214, 216 may be onChain B, and two LEDs 218, 220 may be on Chain C. This method may beapplicable for other numbers of LEDs in each chain. Each chainpreferably has an equal number of LEDs. Three paths D, E, F may bepass-through circuits without components.

Additional paths G, H, I, J, K, L, M, N and O may be part of the LEDpower regulation circuits. They may be low current circuits. OnePositive Temperature Coefficient thermal conductive trace (PTC) may bein each of three circuits G, H and I. One PTC 222 may be in a firstcircuit G, one PTC 224 may be in a second circuit H, and one PTC 226 maybe in a third circuit I. Each thermal conductive trace may be physicallylocated in the proximity of one of the LEDs in each chain, such as thefirst LEDs 210, 214, 218 in each chain. Since the second LED in the samechain may be driven by the same current, it may be assumed to have asimilar thermal dissipation characteristics and therefore similartemperature response. In this manner, a single PTC may be used for eachcircuit, which lowers the component count when compared to monitoringevery LED.

There may be one resistance trace 228, 230 and 232 in each of thecircuits, J, K and L respectively. These PTC thermal conductive tracesand resistance traces may be used to control a current through the LEDchains, A, B and C via a circuit shown in FIG. 23. This prevents theoverheating of the LEDs and prolongs its working life. This LEDtemperature regulation method is discussed in further detail infollowing sections.

Three circuits M, N and O may be without components and may be used tobring electrical connections between pins of the right connector 236 andpins of the left connector 234.

FIG. 22 shows an exemplary powering scheme for a six-LED fixture with afifteen pin input connector 234 and a fifteen pin output connector 236.The output connector shown has jumpers 250, 252, 254 for connecting eachof three LED chains A, B, C to each of three return paths D, E, Frespectively. Three other jumpers 256, 258 and 260 each connects two PTCcircuits G, H, I, J, K, L to one return path (G and J to M; H and K toN; and I and L to O respectively).

Input pins P1, P2, P3 each preferably supplies current to one of the LEDchains A, B and C respectively and hence through jumpers 250, 252, 254to three other pins P4, P5, P6. The input connector and the outputconnector are preferably of opposite gender. This choice allows theinput connector of a second fixture be connected to a first fixtureoutput connector without an intermediate piece.

FIG. 23 shows an example of such a two-fixture connection scheme.Jumpers 250, 252, 254, 256, 258 and 260 may be used at the outputconnector 236 for the second fixture. In this example, there would betwelve LEDs, six thermistors and six resistors in total. The powersupply connection at the first input connector 234 would remain the sameas for the circuit of FIG. 22. This connection scheme can be extended tocascade multiple fixtures in series. Six jumpers 250, 252, 254, 256, 258and 260 may be used at the output connector 236 for the last fixture.

This circuit design and connection scheme allows fixtures to be modular.A long fixture can be composed of multiple shorter fixtures connected tothe right hand side and terminated with a consistent jumper design.

Multi-Chain LED PLM Driver

FIG. 24 shows an exemplary LED driver circuit for a fixture for poweringthree chains A, B and C separately, each by a driver chip, U1A, U1B andU1C. An exemplary chip driver is a National Semiconductor integratedcircuit LM3414HV or LM3414 with Pulse Level Modulation (PLM). Eachdriver circuit may have three resistors R1, R2, R3, one schottky diodeD1, one inductor L1, one capacitor C2, one transistor Q1, and oneprinted thermally responsive resistance trace T1. One resistance R1preferably is a printed resistance trace. The suffixes A, B and C toeach of these components signify an association to a corresponding oneof the three driver chips U1A, U1B, and U1C. The maximum input voltage(Vin) for an LM3414HV may be 65V, and for an LM3414 it may be 42V.Thermally responsive traces T1 and printed resistance traces R1 may bediscrete components instead of printed traces.

A printed thermal responsive resistance trace T1 and a printedresistance trace R1 also are shown as items 222, 224, 226 and items 228,230, 232 respectively in FIGS. 21 and 22. The example shown in FIG. 23may have only two fixtures, in which case a single thermal responsivetrace T1A and resistance R1A (FIG. 24) may be a series of componentsshared across two fixtures. Such a thermal responsive trace T1B andresistance trace R1B also are shown as items 224 and 230 in FIGS. 21 and22. A thermal responsive trace T1C and resistance trace R1C also areshown as items 226 and 232 in FIGS. 21 and 22. Where multiple fixturesmay be used, multiple sets of these components may be repeated in eachof the fixtures as shown in FIG. 23.

In FIG. 24, five circuit elements R1, R2, R3, T1 and Q1 (on the lefthand side of integrated circuits U1A, U1B U1C) form a current control toan LED chain (on the right hand side of integrated circuits U1A, U1B,U1C). Resistances R1 and thermal responsive traces T1 form voltagedividers across a constant reference voltage Vcc. When a PTC thermalresponsive trace T1 increases in its resistance value due to rise intemperature, a voltage increases across a base-emitter of transistorsQ1A, Q1B, Q1C. This results in increasing the emitter current flowinginto I_(ADJ) input pin of U1 and thereby decreases the LED current. Areduction of the LED current will reduce the dissipation of heat. Thechoice of values for thermal responsive traces and resistances T1, R1,R2 and R3 determines an operating temperature of the LED strip light.Capacitors C2A, C2B C2C may be bypass capacitors to ground and chosenfor at least 1 uF capable of withstanding 6V or more.

LEDs 210 and 212 in FIGS. 21, 22 and 23 are shown as LED1A and LED1B inFIG. 24 respectively. LEDs 214 and 216 in FIGS. 21, 22 and 23 are shownas LED2A and LED2B in FIG. 24 respectively. LEDs 218, and 220 in FIGS.21, 22 and 23 are shown as LED3A and LED3B in FIG. 24 respectively.

A driver circuit regulates a current supplied to the LED chain and drawsits power from a constant voltage source shown as +Vin and ground. Aresistor R4 sets a PWM frequency. An inductor L1 reduces ripple acrossthe LED chain. When three LED chains A, B and C are powered separately,an LED failure in one would not cause a failure in the other two chains.

In the absence of resistances R1, R2, RT1 and transistors Q1, LEDcurrent may be determined by equation (1)

I _(LED)=3.125×10³ /R ₃ mA  (1)

Where, preferably, 0.35<=I_(LED) max<1.0 amps, and 3125 ohms>R₃>=8929ohms

Incorporating elements R1, R2, RT1 and Q1, the LED current I_(LED) maybe modified to equation (2)

I _(LED)=[((3.125×10³ /R ₃)−I _(EXT))×2490×10³] mA  (2)

I_(EXT) may be a current of about 400 uA through resistor R2, and R2 maybe chosen to satisfy equation (3) after choosing R3 from equation (1).

I _(EXT)=(Vb−Vbe−1.255)/R ₂<1.255/R ₃=(˜400 uA)  (3)

since Vbe ˜0.7V for a silicon bipolar transistor, and the I_(ADJ) pin ofthe integrated circuits U1 may be internally biased at 1.255V.

The emitter current I_(E), of transistors Q₁, may be the same asI_(EXT). Transistor Q1 base current I_(B) may be approximately:I_(EXT)/β, where β is the current gain for transistor Q1. The basevoltage Vb of transistor Q1 may be given by equation (4).

Vb=[(R _(T1) ×R1)/(R _(T1) +R1)]×[(Vcc/R1)−(I _(EXT)/β)] volts  (4)

Since preferably Vcc=5.4V, and for a typical small signal bipolartransistor with V_(CEO)>Vcc and current gain β greater than 100, theequation for the base voltage may be simplified to

Vb=(R _(T1) ×Vcc)/(R _(T1) +R1)  (5)

Resistances R_(T1) and R1 may be chosen to satisfy conditions (6)

Vb>(Vbe+1.255) volts and (Vcc/[R _(T1) +R1])>>1.255/(β×R ₃) uA  (6)

Vb>(0.7+1.255) volts and (5.4/[R _(T1) +R1])>>4 uA

Vb=(5.4×R1)/[R _(T1) +R1]>1.955 volts and [R _(T1) +R1]<<1.35×10⁶ ohms

R1/[R _(T1) +R1]>0.362 and [R _(T1) +R1]<<1.35×10⁶ ohms  (7)

A load on Vcc preferably should be less than 2 mA, and5.4/[R_(T1)+R1]<2×10⁻³.

Therefore [R_(T1)+R1] may be described by equation (8)

1.35×10⁶ >>[R _(T1) +R1]>2.7×10³ ohms  (8)

Cascading Fixtures Deeping Voltage Divider Point, Vb Consistent.

FIG. 23 illustrated two fixtures connected in series. For examples suchas this, values of R₁ and R_(T1) used in equations (7) and (8) would bethe series values of resistances R₁ and R_(T1) from fixture 1 and 2respectively for each of the suffixes. For example:

R ₁(A)=R _(1A)(Fixture 1)+R _(1A)(Fixture 2) for the “A” suffix and R_(T1)(A)=R _(T1A)(Fixture1)+R _(T1A)(Fixture 2)

R ₁(B)=R _(1B)(Fixture 1)+R_(1B)(Fixture 2) for the “B” suffix and R_(T1)(B)=R _(T1B)(Fixture1)+R _(T1B)(Fixture 2)

R ₁(C)=R _(1C)(Fixture 1)+R _(1C)(Fixture 2) for the “C” suffix and R_(T1)(C)=R _(T1C)(Fixture1)+R _(T1C)(Fixture 2)

A design as shown in FIG. 23 allows multiple fixtures to be cascadedwithout changing the voltage divider point Vb. Resistance values R₁ andR_(T1) may stay consistent for each fixture. Therefore equations (1)through (8) define a range of values for components R1, R2, R3, RT1, Q1with suffixes A, B and C in FIG. 24.

The resistor R4 preferably determines a switching frequency fsw, 250KHz<fsw<=1 MHz

20>R4=20×10⁶ /fsw>80 k ohms  (9)

The driver circuit preferably operates in Continuous Conduction Modeoperation (CCM) with LED ON time less than 400 ns. The minimum LEDswitched ON time preferably would satisfy

VLED>=400 ns×fsw×Vin  (10)

Resistance R4 may be selected to satisfy this condition.

An inductor L1 may be part of the Pulse Level Modulation circuit. Aminimum inductance L1 may be used to maintain less than 60% of thedefined average output ripple current. Inductor L1 preferably satisfiesequation (11)

$\begin{matrix}{{L\; 1}>={\frac{\left( {{Vin} - V_{LED}} \right) \times V_{LED} \times 1}{1.2 \times I_{LED} \times {Vin} \times {fsw}}{uH}}} & (11)\end{matrix}$

Where I_(LED)=I_(L)average=Mid point of I L₁ during t_(ON)

Schottky diode D1 preferably would withstand the peak LED current and1.6 Vin.

Single LED Driver Configuration

A fixture circuit as shown in FIG. 21 can also be powered by using onlyone integrated circuit driver U1. Such a design is shown in FIG. 25,which is similar to that of FIG. 24. The component count is reduced by⅔. Component suffices “A”, “B” and “C” are omitted other than for theLED chain.

Such an LED chain may be connected in series to drive all six LEDs allat the same time by a single integrated circuit driver U1. ComponentsR1, R2, R3, R4, Q1, C2, D1, L1 still may be selected using equations (1)through (11) except that the equivalent resistance value of thermallyresponsive traces T1 shown in FIG. 25 may be the series of thermallyresponsive traces 228, 230 and 232 of fixture 1 and 228, 230 and 232 offixture 2. The equivalent resistance of resistance R1 may be the seriesresistances of 222, 224 and 226 of fixture 1 and 222, 224 and 226 offixture 2. For a preferred embodiment as in FIG. 25:

R1(equivalent)=[R(222)+R(224)+R(226)]_(fixture 1)+[R(222)+R(224)+R(226)]_(fixture 2)  (12)

RT1(equivalent)=[R(228)+R(230)+R(232)]_(fixture 1)+[R(228)+R(230)+R(232)]_(fixture 2)  (13)

Such a cascade series, of fixtures each having six LEDs is shown in FIG.26. This arrangement may be achieved by having the same jumpers 250, 252and 254 at the last output connector 236 as in FIG. 23. In addition,there may be additional jumpers 270 and 272 at the first input connector234.

The thermally responsive traces may be connected in series across thefixtures. The jumpers at the last output connector would be items 262,264, 266, 268. The jumpers at the first input connector 234 would beitems 274, 276 and 278.

Input Connector Pin Reduction Circuit

FIG. 27 shows a circuit diagram with six LEDs formed in three chains A,B and C but with a lower pin count to both input connector 280 andoutput connector 282 when compared to the circuit of FIG. 21. Theconnector pin counts may be reduced from fifteen to ten. The circuitsthat form the LED paths would be A, B, C, D, E and F. Circuits D, E, andF would be used for the LED current return path.

PTC Regulatory Circuit Design

In FIG. 27, paths H and J may be low current return signal paths.Positive Temperature Coefficient (PTC) thermal traces 290, 292, 294 maybe connected in series in trace G Each PTC trace may be located inproximity to one LED in each chain. Since the second LED in the samechain may be driven by the same current, it may be assumed to have thesimilar thermal dissipation characteristics and therefore similartemperature response. An arrangement such as this lowers component countcompared to monitoring every LED. Three printed resistance traces 300,302, 304 may be connected in series in signal path I. Both PTC tracesand resistance traces may be used to control a current through the LEDchains A, B, C via a circuit as shown in FIG. 25. Such currentregulation prevents the LEDs from overheating and prolongs their workinglives.

FIG. 28 shows circuit jumpers 250, 252, 254 for connector 282 for threeLED circuits which may be similar to jumpers for connector 236 in FIGS.22 and 23. However, other circuit jumpers 310, 312 for connector 282would be different from jumpers 256, 258, 260, for connector 236 inFIGS. 22 and 23.

FIG. 29 shows an alternate LED driver circuit embodiment using threedrivers. Each of three PTC traces may be located near a first LED foreach respective chain. For example, a first PTC trace 290 may be locatednear LED 210 for Chain A; PTC trace 292 may be located near LED 214 forChain B; and PTC trace 294 may be located near LED 218 for Chain Crespectively. In this manner, the corresponding PTC trace may be used tocontrol the temperature in each chain by controlling the current flowthrough the chain.

Three transistors Q1A, Q1B and Q1C may use a common reference voltageVcc. If each driver chip U1A, U1B, U1C generates a separate reference,the three reference voltages may be “diode-OR'd” to form the singlereference voltage Vcc for the three transistors. In this way, if any ofthe three driver chips U1A, U1B or U1C should fail, another of thedriver chips will maintain the reference voltage Vcc.

FIG. 30 shows an alternate design which uses only one integrated circuitU1 to drive all LEDs using pin connections P1 through P10 (connectorsshown in FIG. 28). The number of LEDs driven by this circuit may begoverned by the maximum output voltage of driver, which may be 65V forLM3414HV and 42V for LM3414. The circuit scheme in FIG. 29 will be ableto drive three times as many LEDs as FIG. 30.

NTC Regulatory Circuit Design

A light fixture regulatory circuit can also be design with negativethermal coefficient printed (NTC) traces. FIG. 31 shows one suchconfiguration that uses three NTC traces 350, 352, 354. These threecomponents may be connected in series in circuit G. Similarly to thearrangement of FIG. 28, jumper 310 may be used across circuits G and H,and jumper 312 may be used across circuits I and J.

The LED driver circuit shown in FIG. 29 can be modified to drive afixture design as in FIG. 32 using NTC traces. In FIG. 29 the positivethermal coefficient traces RT1A, RT1B, RT1C are on the ground side ofthe resistances R1A, R1B, R1C in the voltage divider. In FIG. 32, thenegative thermal coefficient traces RT2A, RT2B, RT2C are on the powerside of the resistances R1A, R1B, R1C in the voltage divider. Sincethese six traces may be within a fixture, a design such as shown in FIG.32 may be achieved by switching connected Pins P7, P10 at the inputconnector 280. Because NTC traces RT2, RT2B, RT2C decrease in resistanceas temperature rises, a rise in temperature in a fixture increases thebase voltage of transistors Q1A, Q1B, Q1C. The currents throughresistors R2A, R2B and R2C increase, and the PLM currents driving theLEDs in each chain would be reduced accordingly.

In a multiple fixture cascade mode, the equivalent values of the tracesmay be connected in series and would be as follows.

RT2A equivalent value=RT2A(fixture 1) and RT2A(fixture 2)

RT2B equivalent value=RT2B(fixture 1) and RT2B(fixture 2)

RT2C equivalent value=RT2C(fixture 1) and RT2C(fixture 2)

R1A equivalent value=R1A(fixture 1) and R1A(fixture 2)

R1B equivalent value=R1B(fixture 1) and R1B(fixture 2)

R1C equivalent value=R1C(fixture 1) and R1C(fixture 2)

FIG. 33 illustrates an alternate LED driver circuit embodiment that issimilar to the single driver circuit design shown FIG. 30. Theembodiment of FIG. 30 may be modified to drive an LED fixture circuitdesign as in FIG. 31 but with NTC traces. PTC traces RT1A, RT1B and RT1Cin FIG. 30 may be replaced by NTC traces RT2A, RT2B and RT2C andswitched in position with resistances R1A, R1B and R1C. The principle ofLED current regulation may be similar to that shown in FIG. 32.

Both PTC and NTC traces may be applied to the circuits of both FIG. 32and FIG. 33. In such cases, the resistances R1A, R1B and R1C in thesefigures may be replaced with PTC traces RT1A, RT1B, RT1C and leaving theNTC traces RT2A, RT2B, RT2C in place as shown in the figures. With thismodification, the voltages at the bases of transistors P8 or P9 wouldrise at a much faster rate when LED temperature rises. This can bethought of as a “push and pull” effect.

Type A Connector

FIG. 34 shows a preferred, type A connector (FIG. 1, item 24). This maybe a female connector 160 with holes 162 and a connector guide 164. Theconnector may be used for interconnection between fixtures. The numberof pins for this connector would depend on the choice of the drivercircuit selected. Other connectors may be used.

Type B Connector

FIG. 35 shows a preferred, type B connector 170. This may be a maleconnector with pins 172 that mate with pins of a female connector (e.g.,FIG. 34, item 160). Other connectors may be used.

Bracket Latch

FIG. 36 shows a preferred bracket (FIG. 1, item 12) which may support afixture and/or secure two fixtures at their joints. Other brackets maybe used.

Intelligent Lighting Fixtures

FIG. 37 shows a concept of intelligent lighting. The concept will bediscussed here in the context of a building, but it may also apply toother location, including outdoor spaces, and the use of a building as adescriptive example is not intended to limit applicability.

People in a lighted region would wear devices for sensing location, suchas wireless RFID badges or chain tags 602, 604, 606, 608, 610. Some maycarry intelligent personal devices 638, 640, such as cell phones,personal digital assistants, remote controls, or other devices not yetinvented with capability for performing location determination functionsas discussed further below. Intelligent lighting fixtures 612, 614, 616,618, 620, 622, 624, 626, 628, 630, 632 each preferably has a uniqueidentifier. Fixtures may be connected to one or more power distributioncenters 634, which in turn may receive power from any source, such as autility power grid 642 or local source. Local sources may includegenerators, photo-voltaic panels, wind turbines, batteries or othersources now in existence or not yet invented. A computer 636 may beconnected to the power distribution controller 634, such as by Ethernetor other connection. The computer 636 may store and process informationobtained from and/or used in the system, including but not limited toinformation pertaining to, or received from, lighting fixtures, badges,intelligent personal devices, power distribution centers, etc.

FIG. 38 shows elements of a room layout which will be used as an examplefor discussing a theory of operation for implementing intelligentlighting. (The use of a room as an example is not intended to limitapplicability of the intelligent lighting concept.) Light fixtures 700,702 and occupants 704, 706, 708 form a network which collects occupantlocation information, such as time-stamped measurements of occupantposition. In an illustrative example shown in FIG. 38, two lightingfixtures 700, 702 are spaced a known distance “R” apart. Beneathfixtures 700, 702, three persons 704, 706, 708 are shown, which for thisdiscussion may be assumed to be on the same floor or other level. Therelative distances K, O between light fixtures 700, 702 and a firstoccupant 704 preferably are measured in real time as will be discussedfurther below. Absolute positions of fixtures 700, 702 preferably areknown. Triangle RKO defines an absolute location of the first occupant704 relative to a frame of reference of the fixtures. Similarly,triangle RPQ defines the absolute location of a second occupant 706 withrespect to the two light fixtures 700 and 702. In this way, positionsmay be determined for all occupants with direct communications to anytwo fixtures.

For occupants that do not have direct communications with two fixtures,such as because of obstruction or interference, position may bedetermined with reference to any other occupant having a known location.For purposes of illustration, assume in FIG. 38 that an obstructionblocks a direct signal path from a third occupant 708 to a lightingfixture 702. The position of the third occupant 708 can be determinedindirectly through either triangle KLM or triangle MNQ. When absolutepositions of the first two occupants 704, 706 are known; the absoluteposition of the third occupant 708 may be also obtained.

Once a position determination network is established and occupants'locations are defined, occupant movements may be determined. One waywould be to update a time-dependent network map and calculate rates ofchange in the triangles defined by the network map. Such method ofmotion detection using two-way radio determination may be more accurateand useful than using traditional infra red (IR) detectors that onlydetect motion. Such detectors typically “time out” if they do not detectmotion for a period of time and shut off their light, even though anoccupant may be present.

A network map allows for coordination of multiple light fixtures toprovide improved light coverage for all occupants. In the example above,occupant 708 does not have direct sensing path with light fixture 702,which implies that light from this fixture might be blocked fromreaching that occupant. The system may control other fixtures to achievedesired lighting levels for that occupant. For a very large space, suchas a conference room or exterior space, all the lights may not turn onif only a small section of the space is occupied. For example, if acompany receptionist assigns a badge to visitor and enters into thesystem a destination location, the badge and the lighting fixture canform part of a system for navigating the visitor to the destination,such as by raising illumination on the path ahead of the visitor, andlowering illumination along diversionary paths.

In the past, traditional light sensors may have been combined with IRmotion sensors with settings for a light threshold level, turn-on timefor a timer, and motion sensitivity level. In such combinations, thepower circuits would have been switched completely off if the ambientlight exceeded a threshold or motion was not detected during the turn-ontimer setting. In comparison, an improved, intelligent lighting fixtureoffers continuous level control of room brightness in real-time with oneof the following methods:

-   -   a) Brightness information on the occupant may be collected from        wireless badges with photo sensors, cameras in cell phones,        portable smart devices with a brightness calibration        application, or other sensors. This information may be fed back        to the lighting system through an information network and may be        a more accurate way for measuring the light level needed by        occupants rather than measuring at fixed wall sensors. The        network can determine a level in lumens needed for each occupant        and coordinate all lights in the vicinity to provide improved        lighting.    -   b) Wall photo sensors may be wired directly to a fixture dimming        circuit or indirectly using a network, such as a power line        network, to provide light level information from wall sensors to        be fed back to the light fixture controller.        In a scenario where no light sensors are present, the lighting        system can estimate its light level by estimating a light output        power required for known distances between the occupants and the        light fixtures.

FIG. 39 illustrates an exemplary control algorithm for light brightness.A light fixture 720 and ambient light both may illuminate a light sensor728. A comparator 726 may determines one or more light threshold levels,such as a minimum and maximum level, or a desired average level. If thelight level increases beyond a threshold, a light dimmer may beactivated. There may be a time delay 724 between the light dimmercontrol 722 and the light sensor comparator 726.

FIG. 40 shows an example of a light sensor circuit, which may use anIntersil ISL29001 sensor 742 sensor, which has a light sensing range ofabout 0.3 lumens to 10,000 lumens, with infrared filtering and 50/60 Hzrejection. Such a sensor has light measurement range from about 0.3 Luxto about 10,000 Lux. It also has infrared rejection and rejection oflight fluctuations in the range of about 50/60 Hz. Other sensors may beused. The sensor preferably reports to a master microcontroller 740through an I2C bidirectional serial communication port. I2Ccommunication uses two open drain lines: a serial clock line 746 and aserial data line 744. Each line may be pulled to the line voltage Vddvia resistors 750, 752. A microcontroller example may be the TexasInstrument MSP430FG4619. Such a controller has 120 KB of Flash RAM and 4KB of ROM and has General Purpose ports for driving LCD displays, I2Ccommunication devices and switches. Other devices can be used, includingbut not limited to a smaller capacity microcontroller MSP430F2013.

Powering A Light Sensor

In the example of FIG. 40, the illustrated microcontroller 740 has anoutput port 748 which may be optional if the light sensor is to bepowered all the time. A resistor 754 may tie the Power Down Pin PD toground to ensure the light sensor is ON. However, if the light sensor isto be turned off for power savings, then the port 748 may be pulledhigh.

Communicating with a Light Sensor

Once the light chip is in an “ON” state, the microcontroller serialclock port 746 may drive the serial clock line SCL. An ISL29001's I2Caddress may be hardwired internally as “1000100”. I2C transactions beginwith the Master asserting a start condition (SDA falling while SCLremaining high). The master drives the following byte to provide a slaveaddress and read/write bit. This particular light sensor requires aminimum of 100 ms for each bit and therefore determines its fastestupdate time. Other devices and protocols may be used.

IR Rejection

A light sensor may be used with a wide spectral response, such as from400 nm to 1000 nm. IR rejection may be a consideration since many lightsources have high presence of IR and these IR sources can give anapparent brightness to which the human eye does not respond. TheISL29001 light sensor may be capable of performing IR rejection because:it has two photodiodes D1 and D2. One diode D1 may be sensitive to bothvisible and IR light (400 nm to 1000 nm), while the other diode D2 maybe mostly sensitive to only IR light. For sensors such as this, a lightmeasurement may be made for the visible range if the light levelreadings from both photodiodes are used according to the followingequation:

D3=1.85*(D1−7.5*D2)

FIG. 41 illustrates an intelligent light fixture controller system withtwo types of network capability: power-line network and wirelessnetwork. A power-line network links together smart devices connected toa common power line. A wireless network connects both portable and otherwireless devices within its RF range or proximity. A power line networkpotentially has a longer range than a wireless network.

Power-Line Communication

Since light fixtures usually draw power from a shared AC power source,power-line networking may be suitable for controlling intelligentlighting fixtures. A power-line network may be based on the concept thatthe power source itself is a communication channel for the network. InFIG. 41, a PT/CT transformer 552 may be a signaling power-line impedancematching transformer. It may be the gateway for a low power controllerblock 580 to communicate with another power-line network device usingthe same AC source.

A preferred low power controller block 580 draws its power from anenergy efficient AC/DC Power Supply 578, which may be directly connectedto an AC power source 556 that preferably is powered at all timesregardless of whether the LED lights of the fixture are powered. Apreferred controller block 580 has a programmable microcontroller at itscore with EEPROM 536 storing a unique ID, a program, a Micro-database598, and a Real-Time Clock 592. It may have several additionalfunctional blocks, such as: Analog to Digital Converter (ADC) 590;Digital to Analog Converter (DAC) 538; Power control with outputtransistor 544 capable of driving a relay 558; Digital I/O ports 596 fordriving an LED driver 568; wireless Digital I/O ports for a WirelessNetwork interface 546; Digital I/O ports for a Sensor Network 548; andports for a 2-way Power-line network 594. This micro-controller systempreferably performs some or all of the following functions:

-   -   a) Line Current Measurements—The micro-controller may sense the        current in the AC source circuit mains 556 through an Isense        port 542 by measuring the voltage across a sensing resistor        Rsense 554 through the Analog to Digital Converter 590.    -   b) Line Voltage Measurements—The micro-controller may sense the        voltage across the AC source circuit mains 556 through an        accurate voltage divider resistor network 550 and picked up by        the controller's Vsense port 540.    -   c) Line Power Measurements—The micro-controller may sense both        incoming voltage and current in real-time, which allows power        consumption to be computed. In the United States, the power        system frequency is 60 Hz. If the sampling is performed on both        current and voltage at least once every 131 uS, which is faster        than 4.32 kHz, the real and apparent power can be calculated        within an accuracy of 10 degree of the phase.

${{Vsense}({RMS})} = \left. \sqrt{}\frac{\sum\left( {{Vsense} \times {Vsense}} \right)}{N} \right.$n = 1  to  N${{Isense}({RMS})} = \left. \sqrt{}{\sum\frac{\left( {{Isense} \times {Isense}} \right)}{N}} \right.$n = 1  to  N Apparent  Power = Vsense(RMS) × Isense(RMS)Real Power=Σ(Vsense×Isense×ΔT1)(energy consumed in 1 second)

-   -   n=1 to N where N=7634, ΔT1=131 uS

Energy Consumption per hour=ΣReal Power

-   -   n=1 to 3600    -   d) Power-line Communications—The micro-controller may have a        bidirectional ability to communicate with other power line        network devices and a central control system through two-way        Power-line network ports 594. The power line network sends data        via a Transmit TX driver 572, and receives commands via a        receive driver RX 574. The power line network modem may be        isolated electrically and protected by blocking capacitors 576        and PT/CT transformer 552.    -   e) Fixture Power Control—The micro-controller may have an output        544 that controls a power relay 558, which in turn controls the        AC input power to drive the LED fixture 570 via a rectified        power bridge 564. The rectifier in turn provides power to an LED        Power Supply 566 and a subsequent LED driver 568, which has        driver controls directly controlled by controller 580. Examples        of LED driver integrated circuits are LM3414HV, LM3464, LM3445,        all from National Semiconductor. Other drivers may be used.    -   f) Temperature regulation—The micro-controller may have a sensor        control port 548 that allows temperature sensors 582 to monitor        the temperatures of the LEDs mounted on the LED light strip 570.    -   g) Real-Time Clock—The micro-controller may have a real-time        clock RTC 592 that runs independently to keep track of time. It        may synchronize occasionally with a central clock through the        power line-network. In addition, the power distribution        center/Power line network center and controller (FIG. 37, item        634) may synchronize with an external reference clock, such as        atomic clock time, time zone, daylight savings time and weather        information from its internet access URL sites to anticipate        times for which a location may be getting ambient light.    -   h) Wired sensors—The micro-controller may have sensor control        ports 548 which allow input from wired sensors 562, such as an        ambient light sensor circuit illustrated in FIG. 40. The        interface shown in FIG. 40 may be serial I2C communication.        These wired sensors may be programmed as slave devices, and the        micro-controller may be programmed as the master device. The I2C        communication architecture allows many devices to share a common        bus. Each device may be distinguished by a unique device        address. Other wired sensors, such as motion sensors, can share        this bus. A temperature sensor 582 for a lighting fixture can be        added to this sensor control for dimming the light with closed        loop feedback. This improves the life of the lighting system.    -   i) Wireless network controller—The micro-controller may have a        wireless network port 546 which may be connected to an optional        wireless module 560 that has six connections similar to those        shown in FIG. 46 and runs a program flowchart similar to the one        illustrated in FIG. 52. Such a wireless module 560 may be        implemented with a wireless network stack, which allows a        flexible dynamic multilink broadcast network scheme described        further below. Such a network scheme overcomes a limitation of        end devices not being able to communicate directly with other        end devices, and it has freedom to join a very large network,        such as a Zigbee network. Such a scheme may be implemented using        a modified SimpliciTI network stack, and this device may be        assigned as an “Access point.” It preferably would be powered at        all times.    -   j) Wireless portable Devices—Portable wireless devices may have        input buttons (switches) 588, screen (optionally a touch        screen), and input sensors 586. A portable device can have a        form factor as simple as a name tag (mobile tag) similar to one        illustrated in FIG. 50, with a program flowchart such as one        shown in FIG. 49. An exemplary circuit diagram is illustrated in        FIG. 46. That example uses a six-connection interface that        allows a portable controller 584 to communicate wirelessly with        the micro-controller 580 via a wireless module 560. There can be        one or more portable wireless controllers, and they all        preferably would have unique addresses and may be assigned as        “End devices” similar to a Zigbee network. They may communicate        with each other automatically and establish a network by a        join-network command and executing a program flowchart, such as        one illustrated in FIG. 49. A portable controller can be larger,        like a handheld remote controller, and be more sophisticated to        include a large touch screen and keyboard entry. It could        include a network interface with cell phones, iphones, etc.        Under such an arrangement, the cell phones and iphones could be        used to communicate with the controller 580 running a custom        application program designed for lighting control. In this case,        users could use their cell phones, iphones, ipads, etc. to be        their portable light controller.

Situation Awareness Dynamic Lighting Illumination Plan

The ability to identify occupants and their activities allowscost-saving illumination plans, especially in large rooms with severallight fixtures and open spaces. FIG. 42 illustrates an example where anoccupant 768 may be stationary under, and illuminated only by, a singlelight fixture 762 with an exemplary illumination light level of threehundred (300) lux in the vicinity of the occupant. The other three lightfixtures 760, 764 and 766 may not be turned on. The light level would belower at locations away from the occupant.

FIG. 43 illustrates an alternate plan where the occupant can choose amoderate savings light illumination plan B. In this example, the twoneighboring lights 780 and 784 are illuminated at light level of twohundred (200) lux, slightly dimmer than the immediate light fixture 782above occupant 788 illuminating at light level of three hundred lux.This allows the occupant to feel not as lonely or isolated. A fixture786 farther away may remain off to provide energy savings.

FIG. 44 illustrates an alternate plan where the occupant can choose anominal savings light illumination plan. In this case, the twoneighboring lights 800, 804 are illuminated at light level of threehundred (300) lux, just as bright as the immediate light fixture 802above occupant 808 illuminating. This allows the occupant to feel good.Fixture 806 remains off as to provide energy savings

FIG. 45 illustrates an alternate plan where the occupant has chosen anominal savings light illumination plan C as he/she begins to walk in adirection to the right. In this case, a neighboring light fixture 820behind the occupant may be reduced to a two hundred (200) lux lightlevel, and light fixtures 822, 824 above and immediately in front of theoccupant 828 may be illuminated at a light level of three hundred (300)lux. A light fixture 826 farther ahead but removed from the occupant 828may turn on to a light level of two hundred and fifty (250) lux. Thiswould allow the occupant to see clearly in the direction where to walkand still provide energy savings

The use of two kinds of communication networks, a power line and awireless network, allows long distance remote control and interactiveresponse to mobile occupants of the room. FIG. 46 illustrates elementsof one exemplary embodiment using a Texas Instruments CC2500 wirelesslow power 2.4 GHz RF transceiver chip 902, which operates in a frequencyband 2400-2483.5 MHz ISM (Industrial, Scientific and Medical) and SRD(Short Range Device) Frequency Band. It allows sixty four (64) bytetransmit/receive FIFOs and can be controlled via a 4-wire SPI interface(SI, SO, SCLK and CSn) serial communication protocol with SPI addressesfrom 0x00 to 0x2E, Such an interface may be used to read and writebuffered data. A 16 bit RISC CPU 900 from an MSP430 family ofmicrocontrollers may be used that provides two additional connections tothe transceiver chip 902 GD02 (an Optional Digital output pin for ClearChannel Indicator), GDO0 (Atest, A digital output pin for test signals),CSn and SI for the I2C. The microcontroller 900 preferably operates in amaster mode while the RF transceiver chip 902 operates in a slave mode.The transceiver may use a 26-27 MHz crystal 904 in a parallel modeoscillation. Typical values for the two crystal loading NPO capacitors906, 908 may be 15 pF 27 pF connected one end to ground. There may betwo RF balun/matching capacitors 910, 918 with values of 1.0 pF+/−0.25pF respectively. There may be two RF balun/matching inductors 912 and914 with values 1.2 nH+/−0.3 nH. There may be one RF LC filter inductor916 with a value 1.2 nH+/−0.3 nH. There may be two RF LC filter/matchingcapacitors 922, 924 with values 1.8 pF+/−0.25 pF and 1.5 pF+/−0.25 pFrespectively. There may be two RF balun DC blocking NPO capacitors 926,928 with values 100 pF+/−5%. A 1% resistor 932 with typical value of 56Kohms may be used for an internal bias current reference. FIGS. 47, 48and 49 illustrate exemplary pin and port assignments for the circuit ifFIG. 46.

Multilink Broadcast Wireless Network

FIG. 50 shows an exemplary flowchart for a microcontroller program in amobile Tag unit. When a tag is powered on, the tag may first initializea radio 1000. Then it may initialize a wireless network 1002. Thewireless network may depend on the network protocol stack that isloaded. A SimpliciTI stack is preferred because a Zigbee stack may bemuch larger, and EEPROM memory space may be limited. All mobile tags maybe assigned as end devices, and the devices at the light fixtures may befully powered access points. Once a stack is established, the mobile tagbroadcasts its presence and listens for a link 1004. The broadcastcommand allows all devices within the reception range to respond with alink action. If there is an access point within its range, the mobiletag will join the network 1006. This may be a typical network join. Theaccess point should generate a member list of all devices in thenetwork. Unlike a traditional join in a Zigbee network, a broadcast mayalso allow a multi-link broadcast network in which end devices (mobiletags) can communicate with other end devices and access points. Such abroadcast capability may be supported by SimpliciTI. An advantage wouldbe that the network can grow to any size and dynamically be formedwithout all the limitations in Zigbee or SimpliciTI. It would allow allmobile tags and all access points in lighting fixtures to form a fullyfunctional network. It preferably would allow a network formation in theabsence of an access point. Mobile tags can detect each other's presencewhen they become members of this network.

Databases and Proximity Map

Each tag should exchange its unique ID 1008 with each other tag and withaccess points. An access point preferably will record the ID and thejoin time 1010 of a the mobile tag based on a Real-Time Clock (RTC) inits local micro database and also record the same event in the tag'smicro database. In turn, the access point in the light fixtures mayutilize Received Signal Strength Indicator (RSSI) information tocalculate new proximity (“vector distance”) map information with each ofthe mobile tags present. The access point then preferably sends thisinformation to the central network server through either a power-lineconnection or a wired/wireless Ethernet network. The server preferablywill aggregate and consolidate new information into a global proximitymap in a SQL or other database.

A proximity map in matrix format stored in mobile tags and globalproximity map generation is described in detail in the U.S. Pat. No.7,598,854. Member's IDs, join times, and proximities may be recorded inthe sever database. The server may use other databases to performadditional functionalities such as:

-   -   a) Implement personalized lighting plan preferences. The ability        for devices to respond is discussed in patent application USP        20090327245.    -   b) Maintain time clocks for hours employees worked at each        location. This facilitates workflow processes and improves        productivity.    -   c) Update a program, such as Microsoft Outlook™ program, of the        present location in the building of a tag. This could, for        example, facilitate the calling of an impromptu meeting.    -   d) Retrieve identities of individuals who come in contact with        each other and allow a trace back to implement disease        surveillance intervention policy especially in a flu season,        such as illustrated in U.S. Pat. No. 7,598,854.    -   e) Allow real-time asset tracking and management for items        bearing a tag and prevent critical items leaving the building.        Lights may turn on and alarm sound if items are moved. This        improves security. Asset management and inventory status        notification is also discussed in U.S. Pat. No. 6,816,074.    -   f) Provide building security, track visitors, and issue alerts        of unauthorized movements.    -   g) Provide automated directions for visitors or new employees        with a building floor plan, which is also discussed in US patent        application, USP 20090327245.

Lighting Plan

With continued reference to FIG. 50, a mobile tag may call upon anaccess point to update its light plan preference (if selected on thebuttons of the tag) or to retrieve a preset preference in the masterdatabase 1012. Then a tag may request an access points to regulate LEDlights according to the chosen light plan 1014. A light level plan maybe selected based on one or more of several parameters, including butnot limited to distance of the tag from a light, time of day, calendardate (including daylight savings), light sensor values (fixed and/ormobile), and positions of lights relative to one another, electricitytariffs (which may change with time of day), etc. Other parameters maybe used. Distance measurements may be computed from RSSI values, whichmay be the measured RF input signal levels in the channel based ontransmission gains in the RX chain at the transceiver. In RX mode, anRSSI value may be read continuously from the RSSI status register untilthe demodulator detects a sync word.

FIG. 51 illustrates an exemplary space, such as a room, hallway,sidewalk, street, etc. where there may be two light fixtures 850, 854;and a calibrating wireless unit 856. If the distance BC between the twofixtures is known, and if the calibrating unit 856 is positioned at aknown location relative to the fixtures (i.e., BD and CD), then thecorresponding RSSI values obtained for the fixtures may be used as areference. Once the RSSI values are calibrated, a person's location 852can determined from the RSSI values using the geometrical relation

AB ² =BC ² +AC ²−2×BC×AC cos(Angle BCA).

In addition, if there is a light sensor on the tag, the tag may reportthe light level to an access point (FIG. 50, item 1016). Access pointsmay update their respective LED light output levels according to thereceived light sensor reading 1018. A tag may check for RSSI valuechanges with respect to an access point 1020. A change in RSSI valuewould indicate motion, and an access point may determine whether the tagis still within a range, such as within the room confines 1022 or if thespace is outdoors, within some other range limit. If a tag is stillwithin range, the tag may request an access point to recalculate itslighting plan 1024. The process of FIG. 50 would return to step 1014 torequest an updated light output according to the applicable plan. If itis determined that the tag has left the room 1030 or relevant space,then the access point may record the tag's disjoin time from the networkand update the database 1032. The access point may return to a periodicbroadcast mode and listen to the link 1004 for the presence of any tags.In the specific case of an indoor space, a tag's leaving one room andentering another room presents another network formation event, andsteps described above may be repeated at a different access point. (Thesame may occur in outdoor spaces.) A network from which the tag departedmay alert a network to which the tag enters as to that tags lightingplan so that the person will have continuous and agreeable light uponpassing through a doorway or otherwise transitioning location.

FIG. 52 illustrates a mobile name tag, which may be an end device. A tagmay be implemented with active RF technology as shown in FIG. 46, thoughother implementations may be used. A tag may bear the name of a personto whom it is assigned, such as “Amy Lee” 1202. A light plan 1204, suchas “P3,” may be displayed on a screen 1206, which allows user to knowthe current light plan. This display 1206 can be implemented using LCDtechnology, LED technology, E-Ink technology, or another technology.E-Ink technology has relatively low power consumption since it consumespower only during switching. A tag may have various buttons 1208 usedfor selecting a light plan and other operations. A selected light plan1204 may be called a “light preference”. Above the screen 1206 may be anopening 1200 through which a light sensor may measure ambient light. Astrip antenna 1210 may be implemented using a flexible circuittechnology and may be embedded in the plastic cover film of the tag.

FIG. 53 shows a flow chart for an exemplary access point in a lightfixture. In a nominal circumstance, the microcontroller and the radiopreferably are switched on in a low power or occasionally a sleep mode.If the unit has never been powered up before, or after a power failure,it may go through an initialization step 1100 for the radio and aninitialization step 1102 for the network. The radio may be listening1104 for someone to enter the access point's service area, such as aroom, corridor, sidewalk, street way, etc. An initial condition may befor the mobile tag to be in a broadcast mode. Upon detecting a tag, anaccess point preferably would provide a link ID 1106 for the new tag tojoin the network. In a broadcast mode, mobile tags may communicate witheach other and join into a network among themselves. Each tag and accesspoint preferably exchanges its ID 1108, captures all the IDs in itsvicinity, and records these events in real-time. The information may besaved in a proximity map in matrix format in one or more microdatabases. Another copy of the information may be sent to a networkserver and merged into a master database 1110. Mobile tags each mayretain a condensed version of portions of the proximity map.

An access point preferably then checks for any new preference selectedby a mobile tag 1112. If yes, the access point preferably updates apreference database at the network server 1118. Otherwise, the accesspoint may retrieve a preference or a default choice from a networkserver database 1114 if the tag does not have an existing one.

An access point may read ambient light levels from existing tags thathave sensors 1120. A fixture may then update the light output levelsaccording to a lighting plan and optimize the output to measured lightlevels 1122. This dynamic lighting control may be capable of respondingto changes in the lighting due to external environment.

An access point may monitor changes in RSSI with the mobile tags 1124 inorder to detect movement of occupants. In the absence of RSSI valuechanges 1124, the access point may optionally go into a low power sleepmode 1134 for a time until waking up 1136 and returning to a step 1104of listening for new tags. But if an RSSI value changes, the accesspoint may evaluate the movement. For example, the microcontroller maydetermine whether a mobile tag is leaving the room 1126 or service area.If a tag did not leave the service area, then the microcontroller maycontinue to coordinate with other vicinity lights to output a moredesirable light level for the occupant 1128. An access point maycontinue to monitor for changes until the occupant leaves the servicearea. When a tag leaves the service area 1130, the link ID may beremoved to indicate a disjoin of the network. The disjoin event may alsobe recorded and entered into the network server database 1132. Theaccess point may then return to the step for looking for a new mobiletag entering the room 1104.

If there are existing mobile tags in the room and there are nomovements, an access point may check for any change in request for alight plan 1116. In this manner, the light fixture may be controlled torespond to requests from the occupant.

It should be noted that the access point also may report the energyconsumption and time of usage 1110.

Master Network Server

FIG. 54 shows an exemplary circuit for a master network server, whichdraws power from AC power source 1250. Such a server may use a personalcomputer, a laptop, an embedded PC, or other computing machine. It maythrough a USB bus or other interface control lighting fixtures, and itmay be used to program portable controls or wireless tags. A preferredserver may communicate with all lighting fixtures through a power-linenetwork and wireless network. Such a server may maintain databases oflighting plans, lighting preferences, and proximity maps, as well ashistories of network events and energy usage. One exemplary masternetwork server may be comprised of the following components:

-   -   a) Controller system 1258. One exemplary system may be based on        a Texas Instruments MSP430 family of controllers with higher        performance than controllers in lighting fixtures. It may        measure its own power/energy consumption and that of an        associated PC via an Analog to Digital Converters (ADC) 1262        with high voltage differential ports 1260, 1264 for measuring        voltages across known resistances, Rsense 1 1252 and Rsense2        1254. A Power-line network 1276 may include an analog to digital        converter (ADC) to receive analog signals through receiver 1272.        It also may transmit Pulse Width Modulation (PWM) signals using        a Digital to Analog Converter (DAC) 1270 through a transmitter        1274. A stored memory EEPROM 1268 preferably is sufficiently        large to maintain a micro-database, keep its unique ID, store a        wireless program stack, and store its program. A stable crystal        may be included to provide an accurate, on-chip clock signal        1286 and timing for a USB controller 1320. A Real-Time-Clock        program 1266 preferably maintains time for the controller and        all its network members. A higher accuracy clock may be achieved        via synchronization with the PC, which in turn synchronizes with        an atomic clock on-line via the Internet or other communication        channel. In addition, the power distribution center/Power line        network center and controller (FIG. 37, item 634) may collect        information about the local time zone, daylight savings time and        weather information from its internet access URL sites to        anticipate the times for which a location may be receiving        ambient sun or sky light. This is beneficial for designing an        appropriate lighting plan and also anticipating future power        demand. If a facility uses solar panels and a battery storage        system to power its lighting system, an appropriate energy        savings plan can be chosen to reduce power draw during peak or        other critical times. Alternately, it can formulate a light plan        that eliminates energy needs from the power grid by not        depleting all the stored battery energy. Such a controller        preferably draws its power from an isolated AC/DC power supply        1256.    -   b) A personal computer or laptop or an embedded PC, preferably        with a USB2.0 or above port 1308 drawing its power from a power        adapter 1306 and AC power connector 1304. In addition, the        computer USB2.0 serial port communicates with a USB Controller        1320 via a USB receptacle Type B 1296 via a transient port        suppressor 1302.    -   c) USB Controller 1320 communicating serially with micro        controller 1258 via signal lines SIN, SOUT, BRXDI and BTXDI, and        a UART 1284. The USB controller 1320 and voltage regulator 1290        may be reset by a reset signal 1292.    -   d) EEPROM 1288 expands the size of the controller memory. The        EEPROM may be a Catalyst part CAT24FC32V1.    -   e) USB Port transient suppressor 1302 prevents voltage surges on        the USB port. The USB Port suppressor may be a Texas Instruments        part SN75240PW.    -   f) Voltage regulator 1290 preferably regulates the voltage from        the USB bus from the computer to a voltage 1294, Vcc=+3.6 volts.        It draws its power from the USB2.0 port via a VBus 1310, which        is connected to the USB2.0 receptacle 1296. The voltage        regulator may be a Texas Instruments part TPS77301DGK.

A wireless network may be constructed from a wireless network module1280 similar to FIG. 46 with its TX port (FIG. 46 item 942) and RX port(FIG. 46 item 944) communicating with the I/O ports 1278 on themicrocontroller 1258.

Master Network Server Flow Chart

FIG. 55 shows an exemplary Master Network Server flow chart. The servermay first initialize a Radio 1400, along with a wireless network and apower-line network 1402. Initialization may involve the stack loading.Next, the server preferably communicates with all the devices currentlyactive in the network 1404. It may then determine whether there is adiscrepancy in the network devices compared to its last known databaserecord 1406. If there is a discrepancy, the server may determine whetherthe discrepancy involves portable devices 1408. In step 1410, the servermay determine whether the current number of devices is greater than orless than the prior number recorded in the database. If the currentnumber of portable devices is less, then the server attempts todetermine to what other location the device may have moved 1412. If thedevice is found in another room or other location, the server updatesthe network table 1416. If the device is not found 1418, the serverattempts to determine whether the device may have left the service areathrough an exit at the last location where the device was detected.(This step may be modified according to service area, e.g., if theservice area is outdoors.) If that location has an exit, the server mayplace device on a list of devices that have left the service area 1420.This list is not a list of missing/failed devices, but may be a list ofdevices assumed to be active and awaiting return to the service area. Ifthere was no exit from the devices last registered location, the devicemay be placed on a list of missing/failed devices 1422. Themissing/failed list is kept, and an alert may initiated for a servicemanager to check whether the battery is dead or the device isinoperative. At this point, the program may return to point “A”, whichis found in FIG. 56 and which is part 2 of the Master Network Serverflow chart.

In step 1416, after the network table has been updated, the process mayproceed to step 1424 to check for any new requests for changes to alighting plan. If a change has been requested, the process may proceedto step 1426 to implement the requested change. After implementing therequested change, or if no change was requested, the process may updatethe server database in step 1430. (If no request for a change was made,the server may nevertheless update the database with a time stamp andother information, such as the location of the employee, etc.) Theprocess may return to point “A”, which is found in FIG. 56.

In FIG. 56, point “A” is a real-time time synchronizing step 1450. Thissynchronization preferably is carried with all non-wireless devicesthrough the server power-line network. Wireless portable devicespreferably synchronize through the wireless intercommunication. In step1452, the server may communicate and update a measurement of energyusage for some or all of the devices on its network and store theupdated information in a master database. In step 1454, the server mayupdate and consolidate proximity maps in the database. In step 1456, theserver may carry out any service requests made by any devices on itsnetwork list. For example in step 1458, the server may update an energyusage chart according to a timetable. The server may update employees'actual time clocks and work dates for accounting purposes. (This may bea more accurate way of recording work hours based on both location andbuilding. Sometimes, an employee may have different jobs in differentbuildings, and they can clock for different rates automatically by thissystem.) The server may analyze light preference statistics and energyconsumption patterns, and the server may correlate the actual daylightof the season. This capability allows behavioral patterns to beidentified and energy savings policies to be implemented. Workerefficiency studies can also be performed, and lighting policies may beadjusted for productivity rather than energy savings if this should bethe policy of the building operator. Compromise workflow solutions canalso be found with this kind of system, such as optimizing forperformance during some time periods and for energy efficiency duringother periods.

In step 1460, the server may update reports. Upon completion, the servernetwork may enter a low power sleep mode 1462 and wake up upon requestor after a pre-determined time. Wake up upon request may be initiatedupon installation of a new device. Step 1464 allows for installation ofa new device. Step 1466 allows for new device registration. In theabsence of new devices, the program can return to point “A.”

In FIG. 55, a step 1408 labeled “B” identified a situation where a newdevice has entered the system, but the device is not a portable device.This could be, for example, a situation where a new light fixture hasbeen installed. However, this new fixture may be added to the systemaccording to steps illustrated in FIG. 57. A step 1500 may determinewhether the new device is a power-line device. If it is, the device maybe registered 1508 in the master database, and the server process mayreturn to point “A” in FIG. 55. If there was no new power-line device,but if a device was removed, the server may determine whether a deviceis to be de-commissioned 1502. If the device is to be decommissioned,the server may remove it from the database. If the device is not to bedecommissioned, then the server may identify it in the database asmissing and initiate an alert to a supervisor of the building or otherperson for resolution. The process may then return to point “A” in FIG.55.

Alternate AC Voltage and Current Measurement Solution

FIG. 58 illustrates an alternate circuit to the one shown in FIG. 41. Inthe circuit of FIG. 41, a microcontroller system 580 measured both ACvoltage and AC current. In contrast, FIG. 58 shows that a circuit mayuse a dedicated Maxim integrated circuit MaxQ3183 1554 for both ACvoltage and current measurements and communicating measured values backto a microcontroller system 1560. In this arrangement, themicrocontroller need not directly interface to the power-line voltagesand be subject to complications associated with voltage spikes anddemands for isolated power and ground. The Maxim IC may also providevarious power measurements, such as apparent and real power, which themicrocontroller system 1560 would no longer need to compute. Thisarrangement would free the micro-controller system to perform otherfunctions. Similar implementation can be for the Master network servershown in FIG. 54.

In the circuit of FIG. 58, the Maxim chip 1554 measures AC line voltage1550 through voltage dividing resistors 1558 The chip 1554 may measurecurrent and power factor through a transformer 1556 connected to itsVcomm, ION and IOP pins. The chip may communicate with themicrocontroller 1560 via an I2C bidirectional serial communication port.Power-line communications in the circuit of FIG. 58 preferably are thesame as in the circuit of FIG. 41. The circuit of FIG. 58 would increasethe capacity of the microcontroller to perform other functions.

The embodiments described above are intended to be illustrative but notlimiting. Various modifications may be made without departing from thescope of the invention. The breadth and scope of the invention shouldnot be limited by the description above, but should be defined only inaccordance with the following claims and their equivalents.

1. A lighting system comprising: (A) at least one lighting apparatushaving a light emitting element capable of emitting a controllablyvariable light output in a region; (B) a position determinationsubsystem capable of determining a position in three dimensions of atleast one mobile entity within the region; and (C) a control subsystemcapable of variably controlling a light output of the at least onelighting apparatus according to the position of the mobile entity.
 2. Asystem as in claim 1 wherein: (A) the system includes a plurality oflighting apparatus, each having a light emitting element capable ofproducing a controllably variable light output; and (B) the controlsubsystem is capable of controlling each lighting apparatus to avariably distinct light output according to the position of a mobileentity.
 3. A system as in claim 1 wherein: (A) the positiondetermination subsystem is capable of determining positions in threedimensions of a each of a plurality of mobile entities; and (B) thecontrol subsystem is capable of variably controlling the lightingapparatus output according to the positions of a plurality of mobileentities.
 4. A system as in claim 1, wherein (A) the system includes aplurality of lighting apparatus, each having a light emitting elementcapable of producing a controllably variable light output; (B) theposition determination subsystem is capable of determining positions inthree dimensions of a each of a plurality of mobile entities.
 5. Asystem as in claim 1 wherein the control subsystem is capable ofcontrolling each lighting apparatus to a distinct light output accordingto positions of a plurality of mobile entities.
 6. A system as in claim1 wherein the position determination subsystem includes at least onemobile electronic element actively engaged with at least one fixedelement to determine the position of the mobile entity.
 7. A system asin claim 6 wherein the position determination subsystem determinesposition of the mobile entity at least in part by radio ranging betweenat least one fixed element and the mobile electronic element.
 8. Asystem as in claim 6 wherein the position determination subsystemincludes at least three electronic elements each determining a range tothe mobile electronic element.
 9. A system as in claim 6 wherein a firstmobile electronic unit engages in determining a range to a second mobileelectronic element.
 10. A system as in claim 6 wherein at least onefixed element is co-located with at least one lighting apparatus.
 11. Asystem as in claim 6 where the control subsystem controls the lightoutput of a lighting apparatus according to an input received from amobile electronic element.
 12. A system as in claim 11 wherein an inputfrom a mobile electronic element includes a measure of light level atthe mobile electronic element.
 13. A system as in claim 11 wherein aninput from a mobile electronic element includes a selection from aninterface to a human.
 14. A system as in claim 4 further comprising adatabase storing information about lighting fixtures, saidlighting-fixture information including information selected from the setof: (A) a lighting fixture identity; (B) a lighting fixture location;and (C) a lighting fixture power level.
 15. A system as in claim 4further comprising a database storing information about mobile entities,said mobile-entity information including information selected from theset of: (A) a mobile entity identity; (B) a mobile entity position; and(C) a mobile entity lighting plan input.
 16. A system as in claim 1further including a computer communicating with the at least onelighting fixture through a power line.
 17. A system as in claim 1wherein the position determination subsystem determines proximity of onemobile entity to another mobile entity.
 18. A system as in claim 1wherein the position determination subsystem determines position byradio ranging and triangulation.
 19. A lighting fixture comprising: (A)at least two series chains of light emitting diodes, (B) at least onecontroller circuit that produces an output power to the light emittingdiodes that varies according to (i) a lighting plan and (ii) a thermallyconductive trace. (C) a ranging circuit that determines a range to amobile entity; (D) an access point to a network; (F) at least oneelectrical connector that allows interconnection of thermally conductivetraces from a second lighting fixture; (G) a mounting bracket selectedform the set of (i) a corner bracket, (ii) a hanging bracket, (iii) anda ceiling mounted bracket; (G) a rotating access block; and (H) atilting reflector.
 20. A mobile electronic unit for use in a lightingsystem, said mobile electronic unit comprising: (A) a ranging circuitcapable of engaging with at least one other element to determine theposition of the mobile electronic unit; (B) an interface through which ahuman may provide an input useful for setting a lighting level; and (C)a light sensor measuring a light level.